Dairy cows rapidly increase amounts of their milk from immediately after calving to the prior period of lactation to recover their bodily strength in the puerperal period. Accordingly, the energy consumption of dairy cows reaches the maximum, and the nutrition demand is physiologically increased. Despite this, even normal healthy dairy cows reduce the appetite owing to their puerperium, and the feed intake is temporarily reduced. Consequently, although the energy and the nutrient are not sufficiently supplemented, the energy consumption is great, so that the energy balance becomes minus and the insufficient nutrition occurs. As a result, dairy cows naturally try to supply the energy upon using all of their body fats. Unless the metabolism in the body proceeds smoothly, ketosis or an abomasum displacement occurs. The energy is used preferentially in the order of body maintenance, lactation and breeding. When the energy balance is in the minus condition, it causes the decrease in the body weight of dairy cows, diseases and environmental stress, as well as the delay of the first estrus of dairy cows and the ovary function disorder thereof, influencing the breeding results (Mizomoto K., Dairy Japan, February 1993, extra edition).
Yasuho states that ruminants tend to suffer from abnormal metabolism of sugar and lipid, such as ketosis at the peak stage of lactation or at the final stage of conception (New Chemistry of Dairy Cows, Noson Gyoson Bunka Kyokai, published Jul. 15, 1987). He further states by citing Krebs (1996) that when glyconeogenesis increases in the liver, the formation of ketones increases.
In the diabetic complication that risks the life, ketones (D-3-hydroxybutyric acid, acetoacetic acid and acetone) are formed, and proton at a high concentration that exceeds an acid-base buffer system of the body is formed, resulting in the dangerous decrease in the pH of the blood. Although ketones have been considered to be metabolic wastes, it is currently known that ketones are used as a fuel in addition to ordinary fuel glucose of the brain in the fasting. The controlled formation of ketones induces ketosis. In the ketosis, the pH of the blood remains buffered in the normal range. This is quite an important glucose saving to the fasting. Since the brain cannot use fatty acid as a fuel, glycogen stored comes to be exhausted ("Easy Metabolism, Basic Knowledge of Nutrient Metabolism" translated by Aso Y.).
G. D. Baird (J. Dairy Sci. (65) 1-10, 1982) states that the increase in the concentration of ketones in the blood has an adverse effect on breeding of dairy cows.
Baalsrud (Nils-Ivar Baalsrud, U.S. Pat. No. 3,959,496) discloses that before or after calving of dairy cows, the actual amount of milk is not balanced with the amount of milk produced from the energy inherent in dairy cows and the actual amount of milk is increased from 1 month before calving to 5 months after calving, with the result that the energy balance of dairy cows is lost during this period, the consumption is increased and the overall energy balance is minus. It is further stated that a rumen-bypassed biologically active substance and glucose are administered to improve this.
Kato discloses that since excess intake of proteins in dairy cows in the peak period of lactation deprives the energy of dairy cows, the energy loss of dairy cows greatly influences the breeding, that a protein decomposed in a rumen becomes ammonia and is used by bacteria in the rumen but excess ammonia is detoxicated into urea in the liver which increases blood urea nitrogen (BUN), and that when the BUN value increases, a sperm, an egg and a fetus (embryo) are seriously influenced and killed (Kato H., Dairy Japan, February 1993, extra edition).
Butler studied a relationship between the BUN value and the conception rate in the first estrous period after 60 days from calving, and reported that the conception rate is 53% at the blood concentration of 19 mg/dl or less, whereas it is decreased to 35% at the blood concentration of more than 19 mg/dl (W. R. Butler et al., J. Anim. Sci. 1996, 74: 858-865).
Meijeijer measured a concentration of a free amino acid in the plasma and the muscle of high-level lactation dairy cows to which a concentrated feed, a corn silage and a predried hay silage were administered from 2 weeks before calving to 15 weeks after calving. As a result, it was found that the concentrations of methionine, phenylalanine, glutamic acid and glutamine in the plasma during the period of from 6 to 15 weeks after calving were reduced by from 16 to 25% as compared with those before calving. The change in the amino acid concentration in the muscle from the later stage of conception to the initial stage of lactation suggested that the protein in the muscle is decomposed because amino acids are supplied to a mammary gland. It is further stated that in the high-level lactation dairy cows, glutamine latently controls the synthesis of a milk protein [G. A. L. Meijeijer et al., J. Dairy Sci., 78, (S), 1131 (1995)].
Torii [Japanese Laid-Open (Kokai) No. 54,320/1988] discloses a pharmaceutical composition which is composed mainly of alanine and glutamine and which is effective for treating anti-alcoholic diseases. Mawatari [Japanese Laid-Open (Kokai) No. 229,940/1993] discloses hepatocyte regeneration accelerating agent which contains alanine or glutamine as an essential ingredient and which can increase hepatocytes to accelerate regeneration of the liver. Mawatari [Japanese Laid-Open (Kokai) No. 221,858/1993] discloses that a hepatitis treating agent containing at least one of alanine, glutamine and ornithine is effective for treating viral hepatitis, drug-induced hepatitis and fulminant hepatitis. Suda [Japanese Laid-Open (Kokai) No. 50,917/1986] discloses an anti-alcoholic liver disorder-treating composition containing alanine and ornithine as active ingredients.
The present invention is to develop a nutrient feed for expediting breeding of dairy cows and a method of expediting breeding of dairy cows by feeding them with the nutrient feed.